Sewing machine



May 21, 1946.

N. v. HRlsTENsEN ETAL SEWING MACHINE Filed April l2, 1943 4 Sheets-Sheetl I INVENToRs y 0R/wmv u cfmzsre/vsf/v BYVcgoRGE .sa UER RN v .Q

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N. v. cHRlsTL-:NSEN Erm. 2,400,741

SEWING MACHINE Filed April l2, 1943 v INVENTORS NUR/VHN V. CHRSTENSf/VBY HUER HTT RNEY Mayzl, 1946. NJ cHRlsTENsN Erm. 4 2,400,741

SEWING MACHINE Filed 'April 12, 1943 4 Sheets-Sheet` 3 l N Il, mi 4 TNUN mmm mb m55 f RM H C0 .E VG .Y Nw, I l AY ..11 MB {IMI} P. W w w A-10,0 -ws /NN Nw uw m A l MN .9h hb... Qm- HN bwl .ww

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INVENToR. NORM/LN MGHR IS TENSE/V BY '0 GEORGE snc/ER Patented May 2.1,1946 SEWING MACHINE Norman V. Christensen, Chicago, and George Sauer,Berwyn,

Ill., assignors to Union Special Machine Company, Chicago, Ill., acorporation of Illinois Application April 12, 1943, Serial No. 482,690

(Cl. Ilz-218) 44- Claims.

This invention' relates to improvements in construction and method ofoperation of a sewing machine, embodying a rotary loop-taking element,and associated devices. It has particular reference to provisions forincreasing the eiliciency and permissible speeds of operation of suchmachines.

A primary object of the invention has been to provide for the effectivecooling or prevention of overheating of the stitch-forming devices ofamachine of the character indicated and to prevent undue wear of suchdevices in the course of normal operation of the machine.

Another object has .been to provide simple and inexpensive means forthev purposes indicated. capable of producing the desired resultswithout any appreciable addition to the cost of opthe lubricant to form,in effect, a lapping comv will now be given in conjunction with vtheaccome eration of the machine or the power required l for suchoperation.

Heretofore, in the operation of machines having rotary hooks, severalobjectionable condi;

tions have arisen to limit the permissible speed of operation of themachine and reduce its norma1 life. Thus, there has been a tendency inhigh speed operations to develop excessive heat in the needle or in thehook, or both. When the needle becomes overheated there is danger ofthread scorching and breakage as well las deterioratlon of 'the needleitself. overheating of the rotary hook renders the raceway lubricantless 30 the operative end of the needle whenever the latter is below thework., The cooling air, sodirected in a most effective manner, isderived, in accordance with the invention, from a blower driven by themotor which operates the sewing machine and the latter arrangement issuch that no appreciable extra load is placed upon the motor.

Moreover, the blast of cooling air is of such character and so directedas toaccomplish various additional beneiicial results. move from therotary hook and the adjacent portions of the machine the small bits oflint which normally have a tendency to accumulate on these parts andinduce wear as well as prevent pound. In dealing with fabrics which areloaded particularly heavily with clay or the like, it is usuallydesirable to eliminate the lubrication of the hook raceway and at suchtimes the cooling action of the blast of air and its tendency to clearaway the particles of dust and lint are especially important.

Other objects, features and advantages of the invention will appear fromthe detailed description of an illustrative form of the same whichpanying drawings, in which:

Fig. I is a view, partly in side elevation and partly in verticalsection, of a sewing machine and its power driven means and associateddevices,Y all shown as mounted upon a supporting table and constructedand arranged in accord- Fig. II is an end view of the construction shownin Fig.v I as viewed from the right.

It serves to rev.

Fig. III is an enlarged detail view showing, in bottom plan, a portionof the construction illustratedin Fig. I, parts of the sewing machinebeing illustrated in section.

Fig. IV is a' face view of the rotary hook embodied in the illustrativemachine and discloses the relationship between the hook and cooperatingneedle at a point in the cycle of operation of .l

the machine, and

Figure V is an enlarged detail view showing in side elevation therelationship between the ro.

tary hook, the needle, and the throat plate in the course of stitchformation, the throat plate being shown in section'. l Referring now tothe drawings, the inventionV has been shown as applied to a lock stitchsewing machine of the type disclosed in the patent to Christensen et al.No. 2,113,572, granted April 12, 1938. This machine comprises a baseportion I 0 providing a work supporting surface which is substantiallyflush with the surface of the top Il of a supporting table. The base, aswill be understood, is mounted in an opening or recess in the tabletop-and may suitably be hingedly mounted on the latter or may simply bepm vided with a flange carried by the peripheral edge of the tableopening. Rising vertically from one end of. the base l0 is a verticalstandard I2 cardle bar I5 is mounted in the needle head and carries atits lower end a needle I6 constituting a part of the stitch forminginstrumentalities. A

-presser foot I1 of suitable construction is mount- -ed at the lower endof a presser bar I1a, which `is also sli'dably mounted in the needlehead and is urged yieldingly downward by an appropriate spring (notshown). For the purpose of operating the needle bar, there is providedwithin the arm I3 a-longitudinally extending shaft I8, the end of whichprojects beyond the vertical standard I2, as shown in Fig. I. To thisshaft may be secured the conventional hand wheel and pulley la'throughwhich power is supplied to the various operating devices of the machine.

As disclosed-in said Christensen et al. patent above mentioned, suitablegearing may be provided between theshaft I8 and a shaft I9 (Fig. III)which extends longitudinally of the base I9. Shaft I9 carries suitableeccentric means cooperating with an eccentric strap 29 and an arm 2iappropriately connected with the work feeding devices of the machine forimparting the feed movement and the lifting and lowering movements tothe feed dog. The latter, which is not shown, may be suitably mountedupon a feed bar 22, which is given the desired movements by the,eccentric means'mentioned above, in the manner `more fully set forth insaid Christensenet al. patent. At an intermediate point there is secured`to the shaft I9 a gear23 which meshes with a pinion24 secured to a hookshaft 25 mounted in a long bearing sleeve-28carried bythe frame of themachine base. The gearing23 and 24, which is enclosed in an oil-tighthousing, as illustrated in Fig. I, iissuch as to impart two revolutionsto the shaft 2li4 for each revolution of the shaft I9 and for eachreciprocation of the needle bar I5. At its forward end the shaft 25carries a rotary i component 21 of a conventional two-to-one rotaryhook. Within the rotary component there is mounted a stationarycomponent 28 constitutmanner disclosed in the pending application ofGeorge Sauer, Ser. No. 442,585, led on May 12, 1942. The mounting mayinclude a plate 34 secured to the top of the housing 33 and having adownwardly extending arm 35 (Fig. II), which is connected by a pivot(not shown) with a downwardly extending arm 36 integral with' a plate 31secured t0 the under surface of the table top. A

bolt 38 pivoted upon the plate 31 and cooperating with a forkedextension of the plate 34 may serve to retain the motor and clutch unitat a desired elevation to provide proper tension on the driving belt, tobe hereinafter described.' i

-The shaft 39 of the motor extends into the clutch housing 33 andcarries adjacent its end a flywheel 49 forming the driving element ofthe clutch. Axially alined with the shaft 39 is a driven shaft 4Icarrying a' driven element 42 of the clutch. Shaft 4 I `is mountedinsuitable bearings within a sleeve 43 carried by an extension 44 of thehousing. The arrangement is such that the sleeve V43 may be shiftedaxially to a limited extent within the support 44. For this purpose pinsor projections 45 carried by the sleeve 43 may extend through elongatedopenings in the portion 44 of the housing and may be engaged by theforked, upper ends of a, bifurcated portion of an operating lever 46pivoted at 46a upon the clutch housing. A spring 41 normally urges thelever 46 in a clockwise direction (Fig. I) to shift the sleeve II3Vtoward the 4right and disengage the clutch. 'I'he lever 46, however, mayb`e rocked'in a counter-clockwise direction in any suitable way, as bymeans of a link 48 connected with a foot treadle.

or thelike, to bring about engagement of the clutch at will.

Secured to the shaft 4I, which is shifted in the manner explained, is apulley 4'9 connected by a ing ya. bobbin holder,` this being heldagainst rotation by a detent 29 (Fig. III) secured to the under side ofthe work support. As will be understood, the hook illustrated is of theraceway type, in which a suitable rib provided on the stationarycomponent cooperates with a groove or raceway in the rotary component.Any suitable means may be employed for lubricating the raceway.

For this purpose there is partially illustrated ln Fig. III a lubricantreservoir 30 mounted beneath the work support and having one end fittedover the,end of a bearing'sleeve 3| in'lwhich the end vof the hook shaft29 is ioumaled. This construction may be of the type illustrated in theapplication of John G. Attwood, Sen-No. 473,804, filed 'on January 28,1943. As disclosed in said application, the construction' maybe suchthat oil may be fed from the reservoir 39 through a longitudinallyextending bore within the shaftv 25 to v the rotating component ofthehook, which upon revolution will cause the `oil to be delivered to theraceway. 1

-For the purpose of driving the sewing machine, there may be' providedbeneath the supporting table II an electric motor 32 having associated g,therewith a power transmitting clutch housing 33. This transmitter unitmay suitably be of the type disclosed in the-Patent No. 2.0372844.granted to Max Y'I'. Voight on April 14. 1936. and it may be mounted onthe under side of the table top in the belt Bli'with the pulley Isasecured to the main drive shaft I8 of the sewing machine. Power is thustransmitted to the sewing machine from the motor 32 whenever the clutchis engaged by the axial shifting of the shaft 4I and clutch member 42. Asupporting plate or frame 5I, preferably of c-shape, as; shown in Fig.II, is adiustably mounted on the clutch housing by a plurality of bolts52. As set forth more fully in the pending Sauer application, abovementioned, this construction is such vas to permit both angular andaxial adjustment oi the plate 5I with respect to the axis of the shafts39 and 4I. A blower housing 53, preferably of the construction set forthin said Sauer-application, is detachably connected i ment o'f theclutch. The adjustment ofthe plate Y 5| in the manner above indicated,allows for the relative shifting of the impeller andblower housing` toeliminate interference between these parts. both in the originalassembly of the parts andlby way of compensation for wear.

'I'he blower housing has an outlet member 59 which is connected.preferably, by a vflexible coupling 89. formed of rubber or a suitablesynthetic composition, with the lower end of a tubular conduit 8 I Thelatter, which may suitably be formed of metal or an appropriate plasticor may simply be a exible hose, preferably, has an internal diameter ofabout 3/4 oi aninchand is shaped or bent, as indicated in Figs. I andII, to extend horizontally along the rear edge oi the table top',

or, V1i! desired, it may be positionedbeneath the table top or within agroove in the under surface side of the table along its rearward edge.Beyond the bracket 63 the tube or conduit is ,bent through a sweepinglycurved portion 64 in such a way as to point its free end in the oppositedirection. Another loop or bracket 65 may be employed to hold a portionoi the tube, adjacent its free end,

against the under surface of the table. The dis-` charge end 66 of theconduit has an outlet of the same' diameter as the conduit as a wholeand is so positioned as to direct the stream of air ,generated by theblower against the outer face of the rotaryhook. Preferably, asshown,'the discharge end of the conduit is directed upwardly andinwardly at a slight angle. The appropriate inclination to thehorizontal maybe established by cutting away the under surface of thetable along the edges at one corner of the opening through which thebase of the sewing machine extends, as indicated at 61 (Figs. I and III)and providing a sloping under-surface 68 V(Fig. I) at the desired angleon the portion of the table engaged by the discharge end of the conduitjust in advance'oi the cut away portion. The spacing of the outlet 66from the face of the rotary hook is preferably about 2 or 3 inches whichis just sulcient to provide ready access to the hook and permit theremoval of the bobbin holder 28 from the rotary component 2l withoutdisturbing the relative positioning of the parts. This is facilitated,furthermore, by the location of the outlet 66 at one side of .the axisof the hook shaft, as shown in Fig. III, The arrangement is preferablysuch that the sewing machine as a whole may be swung backwardly on itshinges or lifted from the opening in the table, to permit access to thebase of the machine, without disturbing Athe conduit. Due to the spacingindicated, between the outlet 66and the face of the hook, the stream ofair discharged from the conduit is permitted to expand in the mannershown by the arrows in Figs. I and III and, thus, complete envelopmentof the rotary hook is insured. A number of desirable effects areaccordingly produced. Firstly, the temperature of the hook is keptwithin desirable limits; secondly, the accumulation of lint and iillermaterial on and within the hook is prevented; thirdly, the needle issubjected to a desirable cooling action whenever the point is carriedbelow the work, and fourthly, lint and ller are blown away from theopenings 69a and 69h (Figures IV and V) in the throat plate 38 throughproper reception of the loop-seizing beak of the' rotary hook. This isillustrated in Figure V. The needle in this figure is'illustrated in theposition -it assumes immediately after it commences its upward movement.This upward movement tends to'form a loop 10 in the needle thread. Im-

mediately thereafter the thread-seizing point, or

beak 1l of the hook enters the loop and thus causes the n'eedle threadto be cast aroundthe bobbin case. The air blown in the direction con,-`templated by the present invention serves to open up the loop 10 byblowing this toward the right in Figure V .away from the needle. Thusproper cooperation between the hook point 1| and the loop 10 is insured.If the blast of air were blown in the opposite direction it wculd'beseen from Figure V that it would tend to close the loop 'ill and thusinterfere with the proper cooperation ofthe hook point 1 I with theloop. The same may beV said with respect to a blast of air directedupwardly from beneath 4the hook, since this passing around and throughthe openings in the hook will have a tendency to cause the loop 10 toilatten out against the needle.

It has been found desirable to discharge the continuous stream ofcooling air at a velocity of between 10 and 100 ft. per second andpreferably between 50 and 70 ft. per second. In the use of a conduit ofthe character indicated an adequate amount of air, say between .1 and .3of a cubic foot per second, may be delivered to the hook with a pressurein the conduit of only about 1.3 inches of` water above atmospheric.Discharge,l in the manner indicated, of the relatively low velocity andlow pressure air through a space of rather large cross-sectional areahas been found to impart a substantial cooling effect to th hook' and tobring about a quite substantial reduction in the temperature of theneedle. It may be noted, `in this connection, that the needle is in aposition in which its pointis accessible to the cooling air, as shown inFig. IV,\for a substantial portion, i. e.,

. fully one-quarter, of each cycle of the machine.

The elimination of lint on and around the rotary hook and from thepassages inthe throat plate y' -eiect of a coating of lint and dustwhich has a tendency to accumulate on the hook.

While. a preferred form of apparatus embodying the invention and apreferred mode of operation have been explained in detail in the.foregoing itwill be understood that numerous variations may be employedin the speciiic construction and arrangement of the parts and 4in themode of attaining the purposes of the invention without departing fromthe general principles and scope of the invention. The terms andexpressions used herein have been used as terms of description and notof limitation.

" We claim:

l. A machine of the class described comprising a work supporting member,needle carrying and operating mechanism arranged to carry a needle toand through work on said supporting member, a rotary hook having abobbin holder beneath said member cooperating with said needle in stitchformation, means associated directly with said machine and including anelectric motor and connections therefrom for driving said needleoperating mechanism and said rotary hook a blower associated with saidelectric duit being xed at only a suillcient distance from said hook toenable ready access thereto for the removal of said bobbin holder. i

2. A machine of the class described comprisling a work supportingmember,y needle carrying and operating mechanism arranged to carry aneedle to and through work on said supporting member, a rotary hookbeneath said 'member co- A Ioperating with said needle in stitchformation, a

power unit associated directly with said machine and including anelectric motor and a clutch, connections from said unit to said machinefor driving said needle operating mechanism and said rotary hook, ablower mounted on said power unit and arranged to be driven thereby tocreate a low pressure stream of cooling air at a velocity between and10G feet per second, and a conduit from said blower to a point adjacentsaid rotary hook for delivering said stream of cooling air and directingthe same substantially normal 3. A machine of thenclass describedcompris-` ing a work supporting member having a throat on. said powerunit and arranged to be driven Y thereby 'to create a low'pressurestream of cooling air at a velocity between 10 and 100 feet per secondand a conduit fromsaid blower to a point adjacent said rotary hookfor'delivering said stream of cooling air and directing the same against'the forward face of said hook, the discharge end of said conduit beingfixed and spaced from said hook only a sufficient distance vto provideready access to said hook, and being directed substantially axially ofsaid hook but upwardly at a small angle toward the under side of thethroat plate, thereby creating a slight outward pressure through saidthroat plate.

4. In apparatus of the class described a supporting table, an openingthrough the' top there-y of, a sewing machine supported by said tabletop and having a base portion adapted to extend through said opening,said machine having a throat plate 'and stitch forming devices includinga needle `arranged to pass through said 'plate and a horizontal axisrotary hook exposedbeneath said table top, a motor and clutch unitcarried by said table beneath said top, driving connections from saidunit to said sewing machine for operating the latter, a blower carriedby said unit and driven thereby to create a low pressure and lowvelocity stream of cooling air, a conduit connected with said blowerextending beneath said table top to a point in front of said hook, thedischarge end of said conduit being iixed and directed upwardly at asmall angle not exceeding 30 to the horizontal substantially in theplane plate, needle carrying and operating mechanism arranged to carryaneedle to and through work o'n said supporting member and then throughsaid throat plate, a rotary hook beneath said member cooperating withsaid needle in stitch formation, a power unit associated directly with.

said machine and including an electric motor and a clutch, connectionsfrom said unit to said machine for driving said needle operatingmechanism and said rotary hook, a blower mounted of the axis of saidhook and arranged to direct said stream of cooling air toward andagainst the forward face of said hook and around the same and indirectlythrough said throat plate, said hook being sutliciently open at itsforward face to provide access of said cooling air to the needle attimes. NORMAN V. CHRISTENSEN.

GEORGE BAUER.

